Grade 6 Mathematics · Unit 8: Equations & InequalitiesStandard 6.AT.8

Lesson 8.2Subtraction Equations

Start hereWords, worked example, and sentence starters

Name Date Period

Learning target I can solve one-step addition and subtraction equations using inverse operations.

Start hereWords for this lesson

Read each word before you begin. Say it out loud.

WordWhat it meansExample
EquationSpanish: Ecuación A math sentence with an equal sign showing both sides are the same. x + 25 = 60 — both sides equal 60 when x = 35
Inverse operationSpanish: Operación inversa Two math actions that undo each other, like × and ÷. − and +
IsolateSpanish: Despejar To get the letter by itself on one side. get m by itself
SolutionSpanish: Solución A number that makes the equation or inequality true. m = 23 checks out
One-step equationSpanish: Ecuación de un paso An equation you can solve in a single step using one inverse operation. x + 4 = 9 is solved in one step: subtract 4 from both sides, so x = 5.
BalanceSpanish: Equilibrio Keeping both sides of an equation equal by doing the same thing to each side. If you subtract 4 from the left side, you must subtract 4 from the right to keep balance.

How it worksWorked example

These numbers are not on your problems. The steps are. Follow them with your own numbers.

Solve p − 7 = 12.

  1. Add 7 to both sides: p − 7 + 7 = 12 + 7.
  2. Simplify: p = 19.
  3. Check: 19 − 7 = 12.

Answer: p = 19

Say it and write itSentence starters

Finish each sentence out loud with a partner. Then use them in your writing.

  • The variable has subtracted from it, so I to both sides.
  • I kept the equation balanced by .
  • My solution is because .
  • Subtraction and addition undo each other, so .

Word bank equationsubtractaddinverse operationisolatebalanceboth sidesdifferencesolutioncheckundo

Watch out!A common mistake

A common mistake is applying the same operation instead of the inverse

Grade 6 Mathematics · Unit 8: Equations & InequalitiesStandard 6.AT.8

Lesson 8.2Subtraction Equations

Apply Day · Version ASupported practice

Mastery check☐ Exceeds☐ Meets target☐ Needs practice
Name Date Period

Learning target I can solve one-step addition and subtraction equations using inverse operations.

  1. 1Complete each step, then write the final answer.

    Solve n + 12 = 30.

    Show your work

    Hint 12 is added to n. Subtract 12 from both sides.

    Final answer:
  2. 2Complete each step, then write the final answer.

    Solve x − 9 = 16.

    Show your work

    Hint 9 is subtracted from x. Add 9 to both sides.

    Final answer:
  3. 3Complete each step, then write the final answer.

    Solve y + 21 = 50.

    Show your work

    Hint 21 is added to y. Subtract 21 from both sides.

    Final answer:
3-Point Exit Checklist: ☐ 1. Units & Labels Verified ☐ 2. Mathematical Reasoning Stated ☐ 3. Calculations Double-Checked
How did it go? ☐ 4 · I can teach it☐ 3 · I've got it☐ 2 · I need a hint☐ 1 · I need help
Grade 6 Mathematics · Unit 8: Equations & InequalitiesStandard 6.AT.8

Lesson 8.2Subtraction Equations

Apply Day · Version BCore practice

Mastery check☐ Exceeds☐ Meets target☐ Needs practice
Name Date Period

Learning target I can solve one-step addition and subtraction equations using inverse operations.

  1. 1Complete each step, then write the final answer.

    Kai solved x − 12 = 30 and got x = 18. Is he right? What is x?

    Show your work
    Final answer:
  2. 2Complete each step, then write the final answer.

    Solve m + 4.8 = 12.3.

    Show your work
    Final answer:
  3. 3Complete each step, then write the final answer.

    Solve y + 35 = 62.

    Show your work
    Final answer:
3-Point Exit Checklist: ☐ 1. Units & Labels Verified ☐ 2. Mathematical Reasoning Stated ☐ 3. Calculations Double-Checked
How did it go? ☐ 4 · I can teach it☐ 3 · I've got it☐ 2 · I need a hint☐ 1 · I need help
Grade 6 Mathematics · Unit 8: Equations & InequalitiesStandard 6.AT.8

Lesson 8.2Subtraction Equations

Apply Day · ChallengeExtension

Mastery check☐ Exceeds☐ Meets target☐ Needs practice
Name Date Period

Learning target I can solve one-step addition and subtraction equations using inverse operations.

  1. 1Circle the letter of the best answer. Show how you know.

    Which value of n is the solution of n − 18 = 27?

    1. An = 9
    2. Bn = 18
    3. Cn = 27
    4. Dn = 45
    Show your work
  2. 2Complete each step, then write the final answer.

    Ana and Ben solve x + 9.5 = 20. Ana gets 10.5. Ben gets 29.5. What is x?

    Show your work
    Final answer:
  3. 3Complete each step, then write the final answer.

    Solve n − 6.25 = 13.5.

    Show your work
    Final answer:
3-Point Exit Checklist: ☐ 1. Units & Labels Verified ☐ 2. Mathematical Reasoning Stated ☐ 3. Calculations Double-Checked
How did it go? ☐ 4 · I can teach it☐ 3 · I've got it☐ 2 · I need a hint☐ 1 · I need help